MBMS, an important feature introduced in R6 (Release 6) by 3GPP (3rd Generation Partnership Project) organization, is a point-to-multipoint service which can transmit data from a source to several users in some specified range simultaneously, and further share the resources of network including core network and access network, to render services, e.g. multi-media services, to a large number of users who have the same needs with less resources.
After a long period of research and development, MBMS already achieved full implementation in R6, R7 of 3 G system, but it cannot meet the growing demand of services, especially the strong demand on mobile TV services of users and services providers. For improving QoS of MBMS further, and adapting to the new LTE (Long Term Evolution) system, MBMS makes significant improvements on logical architecture, service mode, transmitting method, and channel structure, etc. Therefore, the evolution of R6/R7 MBMS to SAE-MBMS (System Architecture Evolve-Multimedia Broadcast Multicast Service) and LTE-MBMS (Long Term Evolution-MB MS) is experienced.
In eMBMS (Evolved-Multimedia Broadcast Multicast Service), SFN (Single Frequency Network) transmission manner is introduced into access network, which is called MBSFN (Multicast Broadcast Single Frequency Network) transmission manner, wherein, several base stations simultaneously transmit the same data with the same resources and the same wireless configuration (e.g. modulation and coding scheme). These multiple cells for MBSFN transmitting are called MBSFN Area. Using MBSFN transmitting manner can reduce frequency resources, and improve frequency spectrum utilization rate. Meanwhile, diversity effect of transmitting with several cells with same frequency can resolve the problems of the coverage of blind area, enhance the reliability of receiving, and increase the coverage.
In the current R6 MBMS, MBMS control signaling, known as the control signaling transmitting on the MBMS MCCH (Multicast Control Channel), which uses the common signaling transmitting manner, is sent according to the Service ID on the reserved signaling channel, therefore it cannot support MBSFN transmitting.